Fertility life table parameters of different strains ofTrichogrammaspp. collected from eggs of the carob mothEctomyelois ceratoniae

Abstract

Fertility life table parameters were assessed for five populations (strains) of two Trichogramma species, T. embryophagum Hartig and T. principium Sugonyaev & Sorokina, collected from eggs of the carob moth Ectomyelois ceratoniae (Zeller) in Iranian pomegranate orchards. Four combinations of two constant temperatures (25°C, 30°C) and two relative humidity levels (50% RH, 70% RH) were used. The overall intrinsic rate of natural increase (rm) was significantly decreased with decreased relative humidity but was uninfluenced by temperature. The highest and lowest rm values were observed in T. embryophagum from Qum (0.34 Ϯ 0.004) and T. embryophagum from Varamin (0.13 Ϯ 0.01), respectively. Two-way interaction analyses revealed that the strains had significantly different responses in their rm values at different temperatures and relative humidities. In general, rm values were significantly higher at 25°C and 70% RH than at 30°C and 50% RH. The Qum strain of T. embryophagum was the most promising candidate to be considered as a biocontrol agent against E. ceratoniae due to its high reproductive rate (0.27 Ϯ 0.01) at conditions (30°C and 50% RH) similar to the actual climatic conditions in Iranian pomegranate orchards during the major part of the growing season.

The parasitoid Trichogrammatoidea armigera Nagaraja (Hymenoptera: Trichogrammatidae) is a potential candidate for biological control of the millet head miner Heliocheilus albipunctella (de Joannis) (Lepidoptera: Noctuidae) in the Sahel

“…According to Baitha and Ram (1998), temperature of 25°C and 30% RH was found most suitable for both T. armigera longevity and fecundity. As observed in Indonesia, T. armigera has different populations (Bahagiawati et al, 2006) and this could explain differences in life table as reported for other trichogrammatids (Samara et al, 2008;Poorjavad et al, 2011). The development from eggs to adults is completed in 7 days, and this is similar to studies by Manjunath (1972).…”

Biology of Trichogramma marandobai and T. manicobai (Hymenoptera: Trichogrammatidae) in eggs of Erinnyis ello (Lepidoptera: Sphingidae)

“…In Trichogramma, the length of the period from egg to adult mainly depends on temperature but can also be influenced by the origin of the insect, the host, the culture that it was collected, and the adaptation of the species or lineage (Pratissoli et al, 2003;Poorjavad et al, 2011). The highest fertility rates in Trichogramma spp.…”

Influence of reproductive biology on establishment capacity in introduced Hymenoptera species

“…Studies that compared the life history traits of thelytokous and arrhenotokous lineages of Hymenoptera species (Stouthamer and Luck 1993;Wang and Smith 1996;Miura and Tagami 2004;Poorjavad et al 2018) either found a lower or higher intrinsic rate of increase of thelytokous lineages. The link between asexual reproduction and a high population growth rate is not necessarily simple and often varies among species and environmental conditions (Stouthamer and Luck 1993).…”

“…In the arrhenotokous generations of a species with parthenogenetic cycling, reshuffling of alleles can promote adaptation (Plantard et al 1998;Pannebakker et al 2004). Because fast population growth is generally associated with thelytoky (Poorjavad et al 2018), and adaptation with arrhenotoky (North et al 2011), a species alternating between thelytoky and arrhenotoky could experience the benefits of both reproductive strategies.…”

“…Reproductive traits such as sex determination, gametogenesis and mating strategies impact population dynamics (Baker 1955;Maynard Smith 1978;Courchamp et al 1999;Wiernasz et al 2004;Zayed and Packer 2005), adaptation (North et al 2011;Hartfield and Keightley 2012), fitness (Tregenza and Wedell 2002;Mattila et al 2012;Poorjavad et al 2018) and population genetics (Gerrish and Lenski 1998;Rabeling and Kronauer 2013;Arca et al 2015). For these reasons, some have argued that reproductive strategies are one of the factors that influence the capacity of insects to establish (Stouthamer 1993;Holway and Suarez 1999;Aron 2001;Kronauer et al 2012).…”